The present invention relates to refuse container lifting devices, and in particular to refuse cart lifting devices. Refuse containers are often quite heavy, and therefore refuse collection vehicles are generally equipped with refuse container lifting devices to assist the vehicle operator when emptying the refuse containers. However, a refuse collection vehicle may encounter several different types of refuse containers on a given collection route, and the differences in these refuse containers often require the use of separate lifting devices. For example, large commercial refuse containers, or dumpsters, are typically emptied by tipping the container over the edge of the vehicle hopper using a variety of lifting devices, including tipper bars and cable and winch arrangements.
Refuse carts are relatively light refuse receptacles constructed from various plastics and other synthetic materials. Features of refuse carts may include for example hinged covers, locking covers, wheels, and handles in various locations and configurations. Capacities generally range from, for example, 30 gallons to 95 gallons. Refuse carts typically encountered in residential areas are emptied using a refuse cart lifter capable of engaging the refuse cart, lifting it, and inverting the refuse cart to empty refuse into the vehicle hopper.
Many prior refuse cart lifters presented a wide profile and thus protrude from the refuse collection vehicle so as to interfere with the emptying of commercial dumpsters when they are tipped over the edge of the vehicle hopper. Protruding cart lifters also created a hazard for the rear-loading refuse collection vehicle driver when backing up, and the side-loading refuse collection driver when navigating narrow roadways, such as alleys. Some lifter designs have addressed this problem by locating the lifter off to the side of or even completely beneath the refuse collection vehicle hopper. Others attempted to reduce the profile of the refuse cart lifter to address the lifter protrusion issue.
Another problem in the refuse cart lifter industry is that cart lifters typically hang down from the refuse collection vehicle, and therefore reduce the vehicle's ground clearance, particularly on uneven ground. Due to the increased distance of a rear-loading refuse collection vehicle from the rear wheels to the most rearward hopper edge, this part of the hopper regularly makes contact with the ground on uneven terrain. Thus, some lifter designs include a retracted position where the lifter is angled underneath the refuse collection vehicle hopper, rather than hanging straight down. However, this type of design may cause interference with light bars and other structural components of the vehicle hopper. Moreover, these angled designs are not suitable for mounting to flat-walled receptacles, such as intermediate containers. Thus, a refuse cart lifter that retracts to a compact profile and keeps all components forward of the mounting surface would serve to improve the operational ground clearance when mounted on a vehicle, and eliminate costly mounting modifications on vehicles or refuse containers.
Most refuse cart lifters used with rear-loading refuse collection vehicles where ground clearance is of great importance are designed with sliding lower hook mechanisms. These sliding mechanisms retract to decrease the side profile length of the refuse cart lifter in the retracted position. However, sliding mechanisms have an increased susceptibility to contaminants that increase wear and maintenance compared to rotating mechanisms. Thus, a refuse cart lifter designed with increased ground clearance with a rotating lower hook mechanism would decrease maintenance and cost.
Yet another issue involves refuse compaction cycles. Prior cart lifters continuously dump refuse into the portion of the vehicle hopper closest to the refuse cart lifter because these lifters cannot empty the refuse cart a substantial distance into the hopper when dumping. The refuse therefore quickly accumulates near the refuse cart lifter, which requires the vehicle operator to stop collecting carts and compact the refuse to prevent interference with the next lifter dumping cycle. Thus, a lifter that empties refuse carts further into the refuse collection vehicle hopper would decrease the amount of time and energy spent compacting refuse between refuse cart dumping.
A final issue involves maintenance of the lifter. Elevated hydraulic loads associated with some lifters correspond to increased wear and strain on cart lifter systems. Also, some lifter motor designs are readily susceptible to damage from contaminants present in the hydraulic system and eventually require complex repairs or rebuilding that can typically only be performed at the manufacturer's facility. Finally, many lifters use bearings that require regular greasing.
Thus, a need exists in the refuse collection industry for a residential refuse cart lifter that possesses a slim profile, provides improved ground clearance, decreases the amount of time and energy spent compacting refuse between the emptying of successive refuse carts, provides needed lifting capacity at lower hydraulic pressures, requires little maintenance, and is easy to repair or rebuild at the end user's facility.